Direct lift aircraft



Jam 1950 E. A. STALKER DIRECT LIFT AIRCRAFT 2 SheetsSheet 1 Filed Oct.3, 1945 I w I INVENTOR. v

Jan 3, 195G E. A. STALKER DIRECT LIFT AIRCRAFT 2 Sheets-Sheet 2 FiledOct. 5, 1945 INVENTOR. 4azm/ Patented Jan. 3, 1950 w th UNITED STATESPTENT OFFICE 10 Claims.

My invention relates to direct lift aircraft.

It has as an object the provision of means to provide orbital patternsof variations of lift throughout the blade orbit which belong todifferent mathematical families.

It is another object to provide means of changing the pattern of orbitallift variation to ac commodate a change in advance ratio.

Another object is to provide means of changing patterns or orbital jetthrust with changing advance ratios.

Still another object is to provide a blade structure adapted to the liftvarying function.

Other objects will appear from the description and drawings.

I accomplish the above objects by the means illustrated in theaccompanying drawings in which- Figure 1 is a fragmentary side elevationof the aircraft;

Figure 2 is a fragmentary top view of the aircraft;

Figure 3 is a fragmentary view of the huband one adjoining blade showingthe control mechanism, taken along the lateral axis of the aircraft;

Figure 4 is a fragmentary top view of Figure 3;

Figure 5 is a fragmentary view of the associated pilot control;

Figure 6 is a fragmentary section of the hub of Figure 3;

Figure 7 is a section along line 1-! in Figure 6;

Figure 3 is a section through the cam along line 88 in Figure 3 showingthe cam contour;

Figure 9 is a section through the cam along line 99 in Figure 3 showingthe cam contour;

Figure 10 is a section through the cam along line Ill-40 in Figure 3showing the cam contour;

Figure 11 is a section through the cam along line I l-l I in Figure 3showing the cam contour;

Figure 12 is a section of the cam along line 12-42 in Figure 3 showingthe cam contour;

Figure 13 is a fragmentary section of the blade along line 13-43 inFigure 3 shown with the flap actuating mechanism which is inboard of thesection plane;

Figure 14 is a fragmentary section along line l4-l4 in Figure 3; and

Figure 15 is a fragmentary cut-away view of the way plates and theconnecting block.

This invention provides a control of the lift of.

blades which is functionally flexible enough to provide orbitalvariations in lift of the proper magnitude for various ratios of forwardflight speed to peripheral speed of the blades. These ratios arecommonlycalled advance ratios.

Contemporary control of the orbital variation in lift of the blades of ahelicopter rotor is accomplished by a swash plate. Tilting of the plateimposes a sinusoidal variation in lift throughout the orbit for alldegrees of tilting. Hence the patterns of lift variation for differentdegrees of tilt all belong to the same mathematical family.

In my invention the pattern of variation might be sinusoidal for oneadvance ratio and not sinusoidal for another advance ratio. Thenonsinusoidal might follow any mathematical function.

For a given advance ratio there is a proper pattern of lift variation toprovide smooth operation and a cam can be designed to provide thispattern. As soon, however, as the advance ratio changes, the patternprovided by the cam is no longer correct and vibration results.

This invention provides a cam which has a great or infinite number ofcam contours so that as the advance ratio changes the pilot selects anew cam contour. These contours are peripheral about a cylindrical bodyof substantial length transverse to the contours just mentioned. Infact, the cam can be thought of as a great number of cylinders ofvarying contour stacked one upon the other with one cam surface fairedinto the adjacent one.

A contactor rides against the cam surface and its displacements,responsive to the cam contour, governs the orbital variation in lift ofthe blades. As the advance ratio increases, the pilot reduces anyvibration by sliding the contour longitudinally of the contactor. Hecontrols the aircraft generally by shifting the cam bodily eitherlongitudinally or transversely.

The contactor is arranged to make a circuit of the cam contour while ablade makes an orbital circuit about the axis of rotation of the rotor.The main point however is that the contactor tranverses the camperiphery in coordinated relation with the rotation of the blade aboutthe rotor axis.

Another cylindrical cam is employed to govern the propulsive jetdischarged from a slot in the blade so that progressively morepropulsive fluid is discharged from the advancing blade as the machineproceeds from hovering to maximum forward speed.

Figures 1 and 2 show a side elevation and a top view of the aircraftcomposed of the fuselage l and rotor 2. The fuselage consists of themain body 4, the horizontal fin 6, the vertical fins 8, and the wheelsIll. The rotor has three blades I2, 14 and I6 hinged with forks H bypins I8 to hub plate I3 which is fixed to hub shaft 20. Each 3 blade hasa flap 2I hinged along its forward edge for varying the camber of thewings.

Figures 3 and 4 are a side and top view respectively of the controlmechanism which operates the flap 2I and the flap leaf 22 in Figure 14.

The variation in the flap position is accomplished by the cam follower24 which runs on the surface of the cam 26. The radial movements of thefollower as it follows the cam contours actuates the bell crank 28 bymeans of link 38 and crank 32. Crank 32, to which the cam follower 24 ismounted, is held in position relative to the blade by means of bracket34 which is mounted on hub plate I9. Bell crank 28 in turn transmitsmotion to bell-crank 38 by means of the link 48. The bell-crank 38transmits a chordwise motion to rod 42 causing flap 2I to be pivotedabout its hinge 44, thus varying the flap position according to the camcontour. The cam follower 24 is kept in constant contact with thesurface of cam 26 by means of the preloaded spring 46.

The helicopter rotor is to be rotated by a propulsive jet dischargedfrom the slot .23 formed at the junction of the flap 2I and the main,body of the blade. For hovering the slot is to be open wide for allorbital positions of a blade. However as the aircraft assumes forwardflight the slot is to be controlled so that more air or fiuid isdischarged from the blade in the advancing position than in theretreating position so as to improve thepropulsive efficiency. Onlyenough fluid is discharged from the retreating blade to provide theproper amount of lift.

Variation of the slot width is made independent of variation of the flapattitude by the flap construction employed.

The variation in the exit :slot 23 with azimuth position of the blade isaccomplished by varying the position of the flap leaf 22 in Figure 14.This is done by means of the cam 48 and cam follower 58 which is kept incontact with the cam surface by spring 52. The radial movements of thecam produces a spanwise motion on rod 54 by means of push-pull rod 56and bell-crank 58. In turn push-pull rod 54 transmits a spanwise motionto the rod 68 through crank '62. Push-pull rod 68 which is located onthe flap hinge line transmits a spanwise motion to the push-pull rod 64by means of the link 68 and crank 68. This spanwise motion of rod 64causes the connecting link 18 which is connected at one end to theprimary structural element II of the flap and the other end to the rod'64 to assume a slanted position, thus causing the flap leaf 22 to pivotat its hinge point 69 thus moving closer to the main structural memberII of the flap since rod 64 is connected to the flap leaf through theslide bearing I2. Thus the flap leaf position is determined by thecontour of the cam 48.

The cams can be moved in a vertical direction thus changing the contourover which the cam followers run. This change in cam contour makes itpossible to havethe fiap 2.8 and flap leaf 22 in the proper position forall flight speed conditions as well as azimuth positions.

The vertical movement of the cams is accomplished as follows: Cam 48 ismounted on tube 14 which is free to move in a vertical direction. Thisvertical movement is transmitted from a control stick in the cabin viapush-pull rod I6 and crank I8. Cam 26 is caused to move vertically bymeans of Bowden cable .88 which receives its motion from a control stickin the cabin. The motion of the push-pull cable 88 is'transmitted to'thelug 84 which is secured'to drum 88 as shown 4 in Figure 7. This drum 86is free to revolve within drum 88 on which cam 26 is mounted in a mannerwhich permits the cam to move vertically in slots 89 but notrotationally. The rotation of the drum 88 causes cam slots 98 cut intodrum 86 to act on pins 92 to which the cam 26 is fixed, thus causing cam26 to move in a vertical direction. The slots 89 in drum 88 accommodatethe vertical movement of pins 92.

In addition, the angular displacement or lag in flap effectiveness maybe trimmed by mounting the gear 94 on the flap cam drum 88 and drivingthe gear by means of the worm 96 and flexible shaft 98 from a controlmeans in the cabin providing for the flap cam 26 and drum 88 to berotated in either direction.

For maneuvering control of the aircraft the cam .26 is fixed to plateI88 which is mounted on fixed plate I82 for movement .in any directionperpendicular to the axis of rotationof the blades. (Plate I82 is fixedto the aircraft structure I86.) To provide for this movement, plates I88and I82 are equipped with ways. A square block I84 is slideablyaccommodated in two ways one above the other at right angles to eachother. See Figure 15.

The plate I88 is moved by means of the control column I88, Figure 5.Movement fore and aft of the control column I88 is transmitted to plateI88 by means of the push-pull rod H8 and crank II2 which transmits themotion to cables II4 and. I I5 and thus by means of crank I I8 andpushpull rod I28 and crank I22 to plate I88. Crank I22 is connected tothis plate by means of rod I24 which permits the plate to move at rightangles relative to the crank I22.

Movement right and left of the control column transmits a similar motionto the plates I88 by means of the torque tube I26 to which segment I28is fixed .and thus caused to rotate about the center line of the torquetube 1 26 and thus transmitting motion to cables I38 and I32 fixed tosegment I28 which in turn transmits this motion to the plate I88 throughcrank I34, push-pull rod I36 and crank I38. Crank I38 is also attachedto plate I88 by means of a rod I48 which permits motion at right anglesrelative to the crank.

I have now described suitable embodiments of my invention which are nowpreferred. It is to be understood however that the invention is notlimited to the particular construction illustrated and described andthat I intend to claim it broadly as indicated by the scope of theappended claims.

I claim:

1. In combination in a direct lift aircraft, a blade mounted forrotation about a vertical axis, lift varying means to alter the lift ofsaid blade, a cylindrical cam having different camming contours atdifferent cross sections along the longitudinal length thereof, acontactor making running contact with said camming surface and havingits rotation about said cam coordinated with the rotation of said bladeabout its said axis,.said cam over the longitudinal length thereofcontacted by said contactor having progressively and continuouslychanging camming contours transverse to the length thereof, meansoperably connecting said contactor with said lift varying means to varythe lift of said blade in coordination with the changing contour of saidcamming surface, and .means to change the relative longitudinal positionof. said contactor and cam and the offset position of said camtransversely with respect .to said axis.

2. In combination in a direct lift aircraft. a

blade mounted for rotation about a vertical axis, lift varying means toalter the lift of said blade, a cylindrical cam having different cammingcontours at different cross sections along the longitudinal lengththereof, a contactor making running contact with said camming surfaceand having its rotation about said cam coordinated with the rotation ofsaid blade about its said axis, means operably connecting said contactorwith said lift varying means to vary the lift of said blade incoordination with the changing contour of said camming surface, andmeans to displace said cam transversely to said axis while saidcontactor is making a circuit about said cam.

3. The combination as defined in claim 1 including a blade having a mainbody and an adjustable flap forming said lift varying means andsupported in variable relationship to define a slot therebetween, meansto induce a flow of fluid through said slot, said fiap being composed ofan I upper surface hinged to the lower surface, and means to displaceone said fiap surface relative to the other said flap surface and tosaid main body surface to vary the said slot width.

4. The combination as defined in claim 1 including a blade having alower fiap structure forming said lift varying means and having wallsspaced apart vertically and joined at their ends to provide torsionalstrength, an upper surface structure hinged to said lower structure, andmeans to displace said upper surface from said lower surface.

5. The combination as defined in claim 1 in which the lift varying meanscomprises a fiap and a hollow torsion structure having walls extensivealong a major portion of the flap chord, an oppositely positioned outersurface articulated to said structure near its aft end, and means todisplace the forward end of said surface away from said structure tovary the thickness of said flap.

6. In a direct lift aircraft, a blade supported for rotation about anaxis to sustain the aircraft, said blade having lift varying means tovary the blade lift, cam means defining a plurality of cam contours,contact means adapted to follow a said cam contour in contact therewith,said contact means operably relating said cam means to said lift varyingmeans to vary the blade lift according to changes in said cam contour,and means to shift said cam in translation in a direction transverse tothe said axis.

7. In a direct lift aircraft, a blade mounted for rotation about anupright axis, said wing having a movable flap to vary the effectiveangle of attack of said blade, means defining a variable area slot insaid blade, said slot emitting a propulsive jet of fluid, slot varyingmeans to vary the area of said slot independently of movement of saidblade, cam means defining a plurality of cam contours, contact meansadapted to follow a said contour in contact therewith, said contactmeans operably relating said cam means to said solt varying means tovary the slot width according to changes in said contour, and means tosubstitute one of said cam contours for another in contact with saidcontact means.

8. In combination in a direct lift aircraft, a blade mounted forrotation about a vertical axis into advancing and retreating positionstending to give rise to lateral disturbing moments on'the aircraft, andmeans to preclude the occurrence of said unbalanced moments comprisingmeans to vary the lift of said blade, cam means having a plurality ofdifferent camming. contourstat a plurality of different cross sectionsalong the longitudinal length thereof, said camming contours being suchthat axial sections therethrough are defined by opposite curved lines, acontactor making running contact with said cam means at said cammingcontour and having its rotation about said cam coordinated with therotation of said blade about said vertical axis, means operablyconnecting said contactor with said lift varying means to vary theorbital lift of said blade in coordination with the changing shape ofsaid camming contour, and means to change the relative longitudinalposition of said contactor and cam to vary said camming contour incontact with said contactor to provide new orbital patterns of lift.

9. In combination in a direct lift aircraft, a blade mounted forrotation about a vertical axis into advancing and retreating positionstending to give rise to lateral disturbing moments on the aircraft, thedisturbing moments from said blade in said positions varying with theadvance ratio, and means to preclude the occurrence of said unbalancedmoments comprising means to vary the lift of said blade, cam meanshaving a plurality of different camming contours at a plurality ofdifferent cross sections along the longitudinal length thereof, acontactor making running contact with said cam means at said cammingcontour and having its rotation about said cam coordinated with therotation of said blade about said vertical axis, means operablyconnecting said contactor with said lift varying means to vary theorbital lift of said blade in coordination with the changing shape ofsaid camming contour, means to change the relative longitudinal positionof said contactor and cam to provide other said cam contours in contactwith said contactor thereby providing new orbital patterns of lift forother advance ratios, and manual maneuvering control means operablyconnected to said cam means to change the relative position of said camand contactor by a movement between the said cam and contactor in adirection transverse to the first said direction of motion of said cam.

10. In a direct lift aircraft, a blade supported for rotation about anaxis to sustain the aircraft, means for varying the effective angle ofattack of said blade to vary the blade lift, said blade having avariable area slot, means defining a plurality of cams, each said camhaving a plurality of cam contours, contact means adapted to follow acam contour of each said cam in contact therewith, means including saidcontact means operably relating said cam means to said angle of attackvarying means to vary said slot area and said angle of attackindependently according to respective changes in said contours, andmeans to change from one said cam contour to another in contact withsaid contact means EDWARD A. STALKER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,403,624 Pescara Jan. 17, 19221,472,199 Thomson Oct. 30, 1923 1,592,740 Macneil July 13, 19262,156,403 Riviere May 2, 1939 2,372,030 Stalker Mar. 20, 1945 2,381,678Maxwell Aug. 7, 1945

